∵|x-y+2|+(2x+y+4)²=0
且|x-y+2|≥0,(2x+y+4)²≥0
∴x-y+2=0,2x+y+4=0
解得:x=-2,y=0
∴[(2x-y)(2x+y)+y(y-6x)]÷2x
=[4x²-y²+y²-6xy]÷2x
=(4x²-6xy)÷2x
=2x-3y
=2×(-2)-3×0
=-4
∵|x-y+2|+(2x+y+4)²=0
且|x-y+2|≥0,(2x+y+4)²≥0
∴x-y+2=0,2x+y+4=0
解得:x=-2,y=0
∴[(2x-y)(2x+y)+y(y-6x)]÷2x
=[4x²-y²+y²-6xy]÷2x
=(4x²-6xy)÷2x
=2x-3y
=2×(-2)-3×0
=-4